BOTOX!
BOTOX, something we hear very very often these days. Ever paused to think what the name really means?
BO-TOX. BO - Botulinum, TOX - yeah, you guessed it! TOXIN!
It's a toxin! More precisely, a Neurotoxin produced by the anaerobic bacteria called Clostridium Botulinum. Hence, Botulinum Toxin.
Well, you may ask what's the big deal. Here's an excerpt from Harrison's Principles of Internal Medicine, aka the bible of Medicine :
botulinum toxin is one of the most potent toxins ever described and is thought by some to be the most poisonous substance in existence. It is estimated that 1 g of botulinum toxin would be sufficient to kill 1 million individuals if adequately dispersed.
Botulinum toxin can be produced pretty easily in laboratories and it's extremely high mortality makes it the perfect bioweapon. In fact, experiments have been conducted in the 1930s by a Japanese Biologic Warfare group on their prisoners.
The United States and the Soviet Union both acknowledged producing botulinum toxin, and there is some evidence that the Soviet Union attempted to create recombinant bacteria containing the gene for botulinum toxin. In records submitted to the United Nations, Iraq admitted to having produced 19,000 L of concentrated toxin—enough toxin to kill the entire population of the world three times over. - Harrison's Principles of Internal Medicine
Despite being deadly at high doses, at controlled doses the same Botulinum Toxin is a treatment modality for multiple diseases, ranging from certain types of muscle spasticity to Achalasia Cardia of the Esophagus to Wrinkles on the Face!
What makes the Botulinum Toxin so versatile? It must be some complex ritualistic mechanism it performs, no? No. It's very very simple actually. This toxin does primarily ONE thing in the body.
In the nerve endings there are vesicles containing a neurotransmitter called Acetylcholine. It prevents the fusion of these vesicles with the cell membrane and thus stops its release of from nerve endings at neuro-muscular junctions.
Again, just one neurotransmitter. What's the big deal! Nothing really, except that every single skeletal muscle that does not get the release of Acetylcholine (ACh) from the nerve innervating it, will not contract. Period.
If I cut down the ACh supply to you biceps, you can't move your arms. No ACh to your quadriceps, you can't walk. Without ACh, basically the skeletal muscles become floppy, relaxed....paralyzed. This form of paralysis is called "Flaccid Paralysis."
This is not permanent, once the toxins get broken down, or the antidote is given, you can start moving your arms again, walk. So why is it so deadly?
As fate would have it, there is a very important skeletal muscle in our body known as the "Diaphragm." Wanna guess what it does?
Along with a little help from Intercostal Muscles of the chest wall (which are also skeletal muscles btw!) it plays a major, major role in breathing. If the paralysis hits your Diaphragm, you simply stop breathing.....and die. This makes it essential to give the antidote after botulinum toxin poisoning ASAP, before it hits the Diaphragm.
Its most widely known Therapeutic Use, BOTOX
The most widely known use of the botulinum toxin is BOTOX for the skin wrinkles. Now you can already understand how it works for wrinkles. A BOTOX injection will relax the muscles of the face by cutting down the supply of ACh to the facial muscles. As the injected muscles will not be able to contract, the wrinkles will disappear.
References :
Harrison's Principles of Internal Medicine, 20th Edition
Davidson's Principles and Practice of Medicine, 23rd edition
Lange Review of Medical Microbiology and Immunology, 13th Edition
